Don't use %p when generating disassembly in vm service.

Evidentally it is platform dependent -- it seems to include the 0x
prefix on mac but not on windows.  I've switched to using %" Px "
instead.

This will fix bug 24038.

BUG=
[email protected]

Review URL: https://codereview.chromium.org//1282993002 .

Author: turnidge

runtime/observatory/lib/src/service/object.dart

@@ -3365,7 +3365,7 @@ class Code extends HeapObject {
       var pcOffset = 0;
       if (disassembly[i] != '') {
         // Not a code comment, extract address.
-        address = int.parse(disassembly[i]);
+        address = int.parse(disassembly[i], radix:16);
         pcOffset = address - startAddress;
       }
       var instruction = new CodeInstruction(address, pcOffset, machine, human);

runtime/observatory/tests/service/service.status

@@ -6,10 +6,6 @@
 evaluate_activation_test/instance: RuntimeError # http://dartbug.com/20047
 evaluate_activation_test/scope: RuntimeError # http://dartbug.com/20047
 
-# Unexpected number format: http://dartbug.com/24038
-[ $system == windows ]
-code_test: Skip
-
 # Disable on simulators.
 [ $arch == simarm || $arch == simmips || $arch == simarm64]
 *: SkipSlow

runtime/platform/globals.h

@@ -306,6 +306,13 @@ typedef simd128_value_t fpu_register_t;
 #define Pu64 PRIu64
 #define Px64 PRIx64
 
+// Zero-padded pointer
+#if defined(ARCH_IS_32_BIT)
+#define Pp "08" PRIxPTR
+#else
+#define Pp "016" PRIxPTR
+#endif
+
 
 // Suffixes for 64-bit integer literals.
 #ifdef _MSC_VER

runtime/vm/disassembler.cc

@@ -46,12 +46,11 @@ void DisassembleToJSONStream::ConsumeInstruction(char* hex_buffer,
                                                  char* human_buffer,
                                                  intptr_t human_size,
                                                  uword pc) {
-  uint8_t* pc_ptr = reinterpret_cast<uint8_t*>(pc);
   // Instructions are represented as three consecutive values in a JSON array.
   // All three are strings. The first is the address of the instruction,
   // the second is the hex string of the code, and the final is a human
   // readable string.
-  jsarr_.AddValueF("%p", pc_ptr);
+  jsarr_.AddValueF("%" Pp "", pc);
   jsarr_.AddValue(hex_buffer);
   jsarr_.AddValue(human_buffer);
 }